HashWire (OpenHFT/Chronicle-Wire 2026.6 API)

java.lang.Object
- net.openhft.chronicle.wire.HashWire

All Implemented Interfaces:

net.openhft.chronicle.bytes.HexDumpBytesDescription, DocumentWritten, MarshallableOut, RollbackIfNotCompleteNotifier, WireCommon, WireOut
```
public class HashWire
extends Object
implements WireOut, net.openhft.chronicle.bytes.HexDumpBytesDescription
```
A specialised WireOut used only for hashing.
Values written to this wire are not serialised. The value writer mixes each item into a rolling hash using constants K0, M0, M1, M2 and M3. An instance is obtained from a thread-local and the hash is cleared on retrieval.

Nested Class Summary
- Nested classes/interfaces inherited from interface net.openhft.chronicle.wire.WireOut
  WireOut.EndOfWire

Constructor Summary

Constructors
Constructor and Description

HashWire()

Constructors
Constructor and Description
`HashWire()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`DocumentContext`	`acquireWritingDocument(boolean metaData)` Retrieves a context for writing either data or metadata, reusing an existing context if available.
`@NotNull WireOut`	`addPadding(int paddingToAdd)` Padding is ignored for hashing.
`@NotNull net.openhft.chronicle.bytes.Bytes<?>`	`bytes()` Unsupported as `HashWire` does not hold an output buffer.
`net.openhft.chronicle.bytes.HexDumpBytesDescription<?>`	`bytesComment()` Not applicable; returns `this` for chaining.
`net.openhft.chronicle.core.pool.ClassLookup`	`classLookup()` Always returns `ClassAliasPool.CLASS_ALIASES` as type resolution is still required for consistent hashing.
`void`	`classLookup(net.openhft.chronicle.core.pool.ClassLookup classLookup)` Sets the `ClassLookup` implementation to be used for class lookup.
`void`	`clear()` Reset the accumulated `hash`.
`long`	`enterHeader(long safeLength)` INTERNAL METHOD, call writingDocument instead
`@NotNull ValueOut`	`getValueOut()` Retrieves the interface for defining the output of a value that will be written to the stream.
`int`	`hash32()` Computes and returns the 32-bit hash value.
`static int`	`hash32(Object value)` As `hash64(Object)` but returning 32 bits.
`static int`	`hash32(WriteMarshallable value)` As `hash64(WriteMarshallable)` but returning 32 bits.
`long`	`hash64()` Computes and returns the 64-bit hash value.
`static long`	`hash64(Object value)` Computes a 64-bit hash for the provided object.
`static long`	`hash64(WriteMarshallable value)` Computes a 64-bit hash for the provided `WriteMarshallable` value.
`long`	`headerNumber()`
`@NotNull WireOut`	`headerNumber(long headerNumber)`
`boolean`	`isBinary()` Determine whether direct access to the underlying byte() makes sense or should it be treated as text
`@NotNull net.openhft.chronicle.core.values.BooleanValue`	`newBooleanReference()` Not supported.
`@NotNull net.openhft.chronicle.core.values.IntArrayValues`	`newIntArrayReference()` Not supported.
`@NotNull net.openhft.chronicle.core.values.IntValue`	`newIntReference()` Not supported.
`@NotNull net.openhft.chronicle.core.values.LongArrayValues`	`newLongArrayReference()` Not supported.
`@NotNull net.openhft.chronicle.core.values.LongValue`	`newLongReference()` Not supported.
`@NotNull ObjectOutput`	`objectOutput()` Get the ObjectOutput associated with this WireOut.
`@Nullable Object`	`parent()` Returns the wire parent object.
`void`	`parent(Object parent)` Assigns the wire parent object for later retrieval.
`@NotNull net.openhft.chronicle.threads.Pauser`	`pauser()` Unsupported by `HashWire`.
`void`	`pauser(net.openhft.chronicle.threads.Pauser pauser)` Not supported.
`void`	`reset()` Alias for `clear()`.
`void`	`updateFirstHeader()` INTERNAL METHOD, call writingDocument instead
`void`	`updateFirstHeader(long headerLen)` INTERNAL METHOD, call writingDocument instead
`void`	`updateHeader(long position, boolean metaData, int expectedHeader)` INTERNAL METHOD, call writingDocument instead
`boolean`	`usePadding()`
`void`	`usePadding(boolean usePadding)`
`boolean`	`useSelfDescribingMessage(@NotNull net.openhft.chronicle.bytes.CommonMarshallable object)` Should this wire write the object as a Marshallable or BytesMarshallable
`@NotNull ValueOut`	`write()` Hashes an anonymous value field.
`@NotNull ValueOut`	`write(@NotNull CharSequence name)` Hashes the field name before returning `valueOut`.
`@NotNull ValueOut`	`write(@NotNull WireKey key)` Writes a WireKey to the stream.
`@NotNull WireOut`	`writeComment(CharSequence s)` Comments do not affect the hash.
`void`	`writeEndEvent()`
`boolean`	`writeEndOfWire(long timeout, TimeUnit timeUnit, long lastPosition)` Write the end of wire marker, unless one is already written.
`@NotNull ValueOut`	`writeEvent(Class<?> ignored, @NotNull Object eventKey)` Hashes the event key and returns `valueOut`.
`boolean`	`writeFirstHeader()` INTERNAL METHOD, call writingDocument instead
`void`	`writeStartEvent()` Start an event object, mostly for internal use.
`@NotNull DocumentContext`	`writingDocument(boolean metaData)` Starts the process of writing a document to the wire with an option for metadata.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.openhft.chronicle.wire.WireOut
dropDefault, endOfWire, padToCacheAlign, writeAlignTo, writeAllAsMap, writeDocument, writeEventId, writeEventId, writeEventName, writeEventName, writeNotCompleteDocument, writingDocument, writingIsComplete

Methods inherited from interface net.openhft.chronicle.wire.WireCommon
newTwoLongReference, notCompleteIsNotPresent, notCompleteIsNotPresent

Methods inherited from interface net.openhft.chronicle.wire.MarshallableOut
builder, methodWriter, methodWriterBuilder, methodWriterBuilder, recordHistory, writeBytes, writeDocument, writeDocument, writeMap, writeMessage, writeMessage, writeText

Methods inherited from interface net.openhft.chronicle.wire.RollbackIfNotCompleteNotifier
rollbackIfNotComplete

Methods inherited from interface net.openhft.chronicle.bytes.HexDumpBytesDescription
adjustHexDumpIndentation, retainedHexDumpDescription, writeHexDumpDescription

- Constructor Detail
  - HashWire
```
public HashWire()
```
- Method Detail
  - hash64
```
public static long hash64(WriteMarshallable value)
```
    Computes a 64-bit hash for the provided WriteMarshallable value.
    
    Parameters:
    
    value - The WriteMarshallable value to be hashed.
    
    Returns:
    
    The 64-bit hash value.
  - hash64
```
public static long hash64(Object value)
```
    Computes a 64-bit hash for the provided object.
    
    Parameters:
    
    value - The object to be hashed.
    
    Returns:
    
    The 64-bit hash value.
  - hash32
```
public static int hash32(WriteMarshallable value)
```
    As hash64(WriteMarshallable) but returning 32 bits.
  - hash32
```
public static int hash32(Object value)
```
    As hash64(Object) but returning 32 bits.
  - classLookup
```
public void classLookup(net.openhft.chronicle.core.pool.ClassLookup classLookup)
```
    Description copied from interface: WireCommon
    
    Sets the ClassLookup implementation to be used for class lookup.
    
    Specified by:
    
    classLookup in interface WireCommon
    
    Parameters:
    
    classLookup - implementation to be used for class lookup.
  - classLookup
```
public net.openhft.chronicle.core.pool.ClassLookup classLookup()
```
    Always returns ClassAliasPool.CLASS_ALIASES as type resolution is still required for consistent hashing.
    
    Specified by:
    
    classLookup in interface WireCommon
    
    Returns:
    
    the current ClassLookup implementation being used for class lookup
  - clear
```
public void clear()
```
    Reset the accumulated hash.
    
    Specified by:
    
    clear in interface WireCommon
    
    Specified by:
    
    clear in interface WireOut
  - reset
```
public void reset()
```
    Alias for clear().
    
    Specified by:
    
    reset in interface WireCommon
  - parent
```
@Nullable
public @Nullable Object parent()
```
    Description copied from interface: WireCommon
    
    Returns the wire parent object. If the parent was not assigned, null is returned instead.
    
    Specified by:
    
    parent in interface WireCommon
    
    Returns:
    
    the wire parent object or null if none was assigned.
  - parent
```
public void parent(Object parent)
```
    Description copied from interface: WireCommon
    
    Assigns the wire parent object for later retrieval.
    
    Specified by:
    
    parent in interface WireCommon
    
    Parameters:
    
    parent - to set, or null if there isn't one.
  - usePadding
```
public void usePadding(boolean usePadding)
```
    Specified by:
    
    usePadding in interface WireCommon
  - usePadding
```
public boolean usePadding()
```
    Specified by:
    
    usePadding in interface WireCommon
  - hash64
```
public long hash64()
```
    Computes and returns the 64-bit hash value.
    This method uses the current hash value and applies an agitation function to provide a consistent and dispersed 64-bit hash result.
    
    Returns:
    
    The 64-bit agitated hash value.
  - hash32
```
public int hash32()
```
    Computes and returns the 32-bit hash value.
    This method derives the 32-bit hash from the 64-bit hash value. The derived hash is the result of XOR-ing the high and low 32-bits of the 64-bit hash.
    
    Returns:
    
    The derived 32-bit hash value.
  - write
```
@NotNull
public @NotNull ValueOut write()
```
    Hashes an anonymous value field.
    
    Specified by:
    
    write in interface WireOut
    
    Returns:
    
    An interface to further define the output for the written value.
  - write
```
@NotNull
public @NotNull ValueOut write(@NotNull
                                        @NotNull WireKey key)
```
    Description copied from interface: WireOut
    
    Writes a WireKey to the stream. This method is typically used for wires that support fields with structured keys.
    
    Specified by:
    
    write in interface WireOut
    
    Parameters:
    
    key - The WireKey to write to the stream.
    
    Returns:
    
    An interface to further define the output for the written value.
  - write
```
@NotNull
public @NotNull ValueOut write(@NotNull
                                        @NotNull CharSequence name)
```
    Hashes the field name before returning valueOut.
    
    Specified by:
    
    write in interface WireOut
    
    Parameters:
    
    name - The CharSequence key to write to the stream.
    
    Returns:
    
    An interface to further define the output for the written value.
  - writeEvent
```
@NotNull
public @NotNull ValueOut writeEvent(Class<?> ignored,
                                             @NotNull
                                             @NotNull Object eventKey)
```
    Hashes the event key and returns valueOut.
    
    Specified by:
    
    writeEvent in interface WireOut
    
    Parameters:
    
    ignored - The expected type of the event to write.
    
    eventKey - The key of the event.
    
    Returns:
    
    An interface to further define the output for the written value.
  - writeStartEvent
```
public void writeStartEvent()
```
    Description copied from interface: WireOut
    
    Start an event object, mostly for internal use.
    
    Specified by:
    
    writeStartEvent in interface WireOut
  - writeEndEvent
```
public void writeEndEvent()
```
    Specified by:
    
    writeEndEvent in interface WireOut
  - getValueOut
```
@NotNull
public @NotNull ValueOut getValueOut()
```
    Description copied from interface: WireOut
    
    Retrieves the interface for defining the output of a value that will be written to the stream.
    
    Specified by:
    
    getValueOut in interface WireOut
    
    Returns:
    
    The interface to further define the output for the written value.
  - objectOutput
```
@NotNull
public @NotNull ObjectOutput objectOutput()
```
    Description copied from interface: WireOut
    
    Get the ObjectOutput associated with this WireOut.
    
    Specified by:
    
    objectOutput in interface WireOut
    
    Returns:
    
    The ObjectOutput associated with this WireOut.
  - writeComment
```
@NotNull
public @NotNull WireOut writeComment(CharSequence s)
```
    Comments do not affect the hash.
    
    Specified by:
    
    writeComment in interface WireOut
    
    Parameters:
    
    s - The comment to be written to the stream.
    
    Returns:
    
    This WireOut instance for method chaining.
  - addPadding
```
@NotNull
public @NotNull WireOut addPadding(int paddingToAdd)
```
    Padding is ignored for hashing.
    
    Specified by:
    
    addPadding in interface WireOut
    
    Parameters:
    
    paddingToAdd - The amount of padding to add.
    
    Returns:
    
    This WireOut instance for method chaining.
  - headerNumber
```
@NotNull
public @NotNull WireOut headerNumber(long headerNumber)
```
    Specified by:
    
    headerNumber in interface WireCommon
  - headerNumber
```
public long headerNumber()
```
    Specified by:
    
    headerNumber in interface WireCommon
  - writingDocument
```
@NotNull
public @NotNull DocumentContext writingDocument(boolean metaData)
```
    Description copied from interface: WireOut
    
    Starts the process of writing a document to the wire with an option for metadata.
    
    Specified by:
    
    writingDocument in interface DocumentWritten
    
    Specified by:
    
    writingDocument in interface MarshallableOut
    
    Specified by:
    
    writingDocument in interface WireOut
    
    Parameters:
    
    metaData - If true, the returned document context will be used for writing metadata.
    
    Returns:
    
    A context for the document being written.
  - acquireWritingDocument
```
public DocumentContext acquireWritingDocument(boolean metaData)
```
    Description copied from interface: WireOut
    
    Retrieves a context for writing either data or metadata, reusing an existing context if available.
    
    Specified by:
    
    acquireWritingDocument in interface DocumentWritten
    
    Specified by:
    
    acquireWritingDocument in interface MarshallableOut
    
    Specified by:
    
    acquireWritingDocument in interface WireOut
    
    Parameters:
    
    metaData - If true, the returned context will be used for writing metadata.
    
    Returns:
    
    A context for the document being written.
  - enterHeader
```
public long enterHeader(long safeLength)
```
    Description copied from interface: WireOut
    
    INTERNAL METHOD, call writingDocument instead
    Start a header for a document
    
    Specified by:
    
    enterHeader in interface WireOut
    
    Parameters:
    
    safeLength - ensure there is at least this much space
    
    Returns:
    
    the position of the header
  - updateHeader
```
public void updateHeader(long position,
                         boolean metaData,
                         int expectedHeader)
```
    Description copied from interface: WireOut
    
    INTERNAL METHOD, call writingDocument instead
    Update/end a header for a document
    
    Specified by:
    
    updateHeader in interface WireOut
  - writeFirstHeader
```
public boolean writeFirstHeader()
```
    Description copied from interface: WireOut
    
    INTERNAL METHOD, call writingDocument instead
    Start the first header, if there is none This will increment the headerNumber as appropriate if successful
    Note: the file might contain other data and the caller has to check this.
    
    Specified by:
    
    writeFirstHeader in interface WireOut
    
    Returns:
    
    true if the header needs to be written, false if there is a data already
  - updateFirstHeader
```
public void updateFirstHeader()
```
    Description copied from interface: WireOut
    
    INTERNAL METHOD, call writingDocument instead
    update the first header after writing.
    
    Specified by:
    
    updateFirstHeader in interface WireOut
  - updateFirstHeader
```
public void updateFirstHeader(long headerLen)
```
    Description copied from interface: WireOut
    
    INTERNAL METHOD, call writingDocument instead
    update the first header after writing headerEndPos bytes.
    
    Specified by:
    
    updateFirstHeader in interface WireOut
  - writeEndOfWire
```
public boolean writeEndOfWire(long timeout,
                              TimeUnit timeUnit,
                              long lastPosition)
```
    Description copied from interface: WireOut
    
    Write the end of wire marker, unless one is already written. This will increment the headerNumber as appropriate if successful
    
    Specified by:
    
    writeEndOfWire in interface WireOut
    
    Parameters:
    
    timeout - throw TimeoutException if it could not write the marker in time.
    
    timeUnit - of the timeout
    
    lastPosition - the end of the wire
    
    Returns:
    
    {code true} if did this method wrote EOF, false if it was already there.
  - bytes
```
@NotNull
public @NotNull net.openhft.chronicle.bytes.Bytes<?> bytes()
```
    Unsupported as HashWire does not hold an output buffer.
    
    Specified by:
    
    bytes in interface WireCommon
    
    Returns:
    
    the underlying Bytes stored by the wire
  - bytesComment
```
public net.openhft.chronicle.bytes.HexDumpBytesDescription<?> bytesComment()
```
    Not applicable; returns this for chaining.
    
    Specified by:
    
    bytesComment in interface WireCommon
    
    Returns:
    
    the bytes() but only for comment
  - newIntReference
```
@NotNull
public @NotNull net.openhft.chronicle.core.values.IntValue newIntReference()
```
    Not supported.
    
    Specified by:
    
    newIntReference in interface WireCommon
    
    Returns:
    
    a new IntValue.
  - newLongReference
```
@NotNull
public @NotNull net.openhft.chronicle.core.values.LongValue newLongReference()
```
    Not supported.
    
    Specified by:
    
    newLongReference in interface WireCommon
    
    Returns:
    
    a new LongValue
  - newBooleanReference
```
@NotNull
public @NotNull net.openhft.chronicle.core.values.BooleanValue newBooleanReference()
```
    Not supported.
    
    Specified by:
    
    newBooleanReference in interface WireCommon
    
    Returns:
    
    a new BooleanValue.
  - useSelfDescribingMessage
```
public boolean useSelfDescribingMessage(@NotNull
                                        @NotNull net.openhft.chronicle.bytes.CommonMarshallable object)
```
    Description copied from interface: WireCommon
    
    Should this wire write the object as a Marshallable or BytesMarshallable
    
    Specified by:
    
    useSelfDescribingMessage in interface WireCommon
    
    Returns:
    
    use Marshallable
  - isBinary
```
public boolean isBinary()
```
    Description copied from interface: WireCommon
    
    Determine whether direct access to the underlying byte() makes sense or should it be treated as text
    
    Specified by:
    
    isBinary in interface WireCommon
    
    Returns:
    
    Is this a binary protocol
  - newLongArrayReference
```
@NotNull
public @NotNull net.openhft.chronicle.core.values.LongArrayValues newLongArrayReference()
```
    Not supported.
    
    Specified by:
    
    newLongArrayReference in interface WireCommon
    
    Returns:
    
    a new LongArrayValues
  - newIntArrayReference
```
@NotNull
public @NotNull net.openhft.chronicle.core.values.IntArrayValues newIntArrayReference()
```
    Not supported.
    
    Specified by:
    
    newIntArrayReference in interface WireCommon
    
    Returns:
    
    a new IntArrayValues
  - pauser
```
@NotNull
public @NotNull net.openhft.chronicle.threads.Pauser pauser()
```
    Unsupported by HashWire.
    
    Specified by:
    
    pauser in interface WireCommon
    
    Returns:
    
    the current Pauser implementation being used for blocking operations
  - pauser
```
public void pauser(net.openhft.chronicle.threads.Pauser pauser)
```
    Not supported.
    
    Specified by:
    
    pauser in interface WireCommon
    
    Parameters:
    
    pauser - implementation to be used for blocking operations.

Class HashWire

Nested Class Summary

Nested classes/interfaces inherited from interface net.openhft.chronicle.wire.WireOut

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface net.openhft.chronicle.wire.WireOut

Methods inherited from interface net.openhft.chronicle.wire.WireCommon

Methods inherited from interface net.openhft.chronicle.wire.MarshallableOut

Methods inherited from interface net.openhft.chronicle.wire.RollbackIfNotCompleteNotifier

Methods inherited from interface net.openhft.chronicle.bytes.HexDumpBytesDescription

Constructor Detail

HashWire

Method Detail

hash64

hash64

hash32

hash32

classLookup

classLookup

clear

reset

parent

parent

usePadding

usePadding

hash64

hash32

write

write

write

writeEvent

writeStartEvent

writeEndEvent

getValueOut

objectOutput

writeComment

addPadding

headerNumber

headerNumber

writingDocument

acquireWritingDocument

enterHeader

updateHeader

writeFirstHeader

updateFirstHeader

updateFirstHeader

writeEndOfWire

bytes

bytesComment

newIntReference

newLongReference

newBooleanReference

useSelfDescribingMessage

isBinary

newLongArrayReference

newIntArrayReference

pauser

pauser